kill invalid tweens before they run

board.gd

@@ -82,6 +82,7 @@ func do_step():
 	pieces_diagonal.sort_custom(magnitude_sort)
 	
 	if last_tween:
+		last_tween.custom_step(413)
 		last_tween.kill()
 	var tween := get_tree().create_tween()
 	last_tween = tween
@@ -93,7 +94,7 @@ func do_step():
 	
 	if pieces_moving.is_empty():
 		# no tweens -> invalid -> annoying error message
-		tween.stop()
+		tween.kill()
 
 func undo_step() -> Callable:
 	var undos: Array[Callable] = []

main.gd

@@ -38,7 +38,7 @@ var advancing := false
 @onready var sounds_undo := audio_stream_randomizer_from_dir("res://sfx/undo")
 @onready var sounds_redo := audio_stream_randomizer_from_dir("res://sfx/redo")
 
-@export_range(0, 1) var slowmo_speed := 0.1
+@export_range(0, 1) var slowmo_speed := 0.2
 
 func _ready() -> void:
 	advance_level()
@@ -52,6 +52,7 @@ func _process(delta: float) -> void:
 		[time, Engine.get_frames_per_second(), move_hold_time, arrf(move_hold_time)]
 	var slowmo := Input.is_action_pressed("slowmo");
 	$SlowmoIndicator.text = "slowmo" if slowmo else ""
+	# TODO: only slowmo during rolltime?
 	Engine.time_scale = slowmo_speed if slowmo else 1.0
 	# TODO: this is kinda comically slow BUT STOP WORKING ON THE GAME
 	AudioServer.playback_speed_scale = slowmo_speed if slowmo else 1.0
@@ -121,7 +122,7 @@ func restart():
 func board_step():
 	hist.add_do_method(board.do_step)
 	hist.add_do_property(self, "time", time+1)
-	hist.add_do_property(self, "time", time+1)
+	hist.add_undo_property(self, "time", time)
 	hist.add_undo_method(board.undo_step())
 
 func step(move: Vector2i):

piece.gd

@@ -25,8 +25,13 @@ func pos_of_lpos(pos: Vector2i, y := 0.0) -> Vector3:
 func target_pos() -> Vector3:
 	return pos_of_lpos(lpos, position.y) + Vector3(0.5, 0, 0.5)
 
+var last_move_tween: Tween = null
 func tween_to_target(tween := get_tree().create_tween()):
+	if last_move_tween:
+		last_move_tween.custom_step(413)
+		last_move_tween.kill()
 	tween.tween_property(self, "position", target_pos(), anim_time)
+	last_move_tween = tween
 
 func lpos_of_pos(pos: Vector3) -> Vector2i:
 	return Vector2i(int(pos.x), int(pos.z))